Method and apparatus for routing path switching in wireless communication system

ABSTRACT

The present disclosure relates to a routing path switching in wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device in a wireless communication system comprises: receiving a configuration for a first routing identity (ID) and a second routing ID, wherein the first routing ID is related to a first routing path towards a destination node, and the second routing ID is related to a second routing path towards the destination node; transmitting, to the destination node, a first protocol data unit (PDU) via the first routing path related to the first routing ID; and based on that a condition to switch a routing path is satisfied: constructing a second PDU so that a header of the second PDU includes information for a routing path switch to the second routing path; and transmitting, to the destination node, the second PDU including the header via the second routing path related to the second routing ID.

TECHNICAL FIELD

The present disclosure relates to a routing path switching in wirelesscommunications.

BACKGROUND

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPPto develop requirements and specifications for new radio (NR) systems.3GPP has to identify and develop the technology components needed forsuccessfully standardizing the new RAT timely satisfying both the urgentmarket needs, and the more long-term requirements set forth by the ITUradio communication sector (ITU-R) international mobiletelecommunications (IMT)-2020 process. Further, the NR should be able touse any spectrum band ranging at least up to 100 GHz that may be madeavailable for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usagescenarios, requirements and deployment scenarios including enhancedmobile broadband (eMBB), massive machine-type-communications (mMTC),ultra-reliable and low latency communications (URLLC), etc. The NR shallbe inherently forward compatible.

In IAB networks, an IAB node may receive a packet from a parent node andforward the packet to a child node. Reversely, an IAB node may alsoreceive a packet from a child node and forward the packet to a parentnode. The forwarding may be referred to as routing or packet routingalong a routing path. However, due to some reasons, the routing path maybecome improper for the packet routing. In this case, a routing pathswitching may be required.

SUMMARY

An aspect of the present disclosure is to provide method and apparatusfor a routing path switching in a wireless communication system.

Another aspect of the present disclosure is to provide method andapparatus for a routing path switching in IAB network in a wirelesscommunication system.

Yet another aspect of the present disclosure is to provide method andapparatus for constructing a PDU a routing path switching in a wirelesscommunication system.

According to an embodiment of the present disclosure, a method performedby a wireless device in a wireless communication system comprises:receiving a configuration for a first routing identity (ID) and a secondrouting ID, wherein the first routing ID is related to a first routingpath towards a destination node, and the second routing ID is related toa second routing path towards the destination node; transmitting, to thedestination node, a first protocol data unit (PDU) via the first routingpath related to the first routing ID; and based on that a condition toswitch a routing path is satisfied: constructing a second PDU so that aheader of the second PDU includes information for a routing path switchto the second routing path; and transmitting, to the destination node,the second PDU including the header via the second routing path relatedto the second routing ID.

According to an embodiment of the present disclosure, a wireless devicein a wireless communication system comprises: a transceiver; a memory;and at least one processor operatively coupled to the transceiver andthe memory, and configured to: control the transceiver to receive aconfiguration for a first routing identity (ID) and a second routing ID,wherein the first routing ID is related to a first routing path towardsa destination node, and the second routing ID is related to a secondrouting path towards the destination node; control the transceiver totransmit, to the destination node, a first protocol data unit (PDU) viathe first routing path related to the first path ID in the first routingID; and based on that a condition to switch a routing path is satisfied:construct a second PDU so that a header of the second PDU includesinformation for a routing path switch to the second routing path; andcontrol the transceiver to transmit, to the destination node, the secondPDU including the header via the second routing path related to thesecond path ID in the second routing ID.

According to an embodiment of the present disclosure, a processor for awireless device in a wireless communication system is configured tocontrol the wireless device to perform operations comprising: receivinga configuration for a first routing identity (ID) and a second routingID, wherein the first routing ID is related to a first routing pathtowards a destination node, and the second routing ID is related to asecond routing path towards the destination node; transmitting, to thedestination node, a first protocol data unit (PDU) via the first routingpath related to the first path ID in the first routing ID; and based onthat a condition to switch a routing path is satisfied: constructing asecond PDU so that a header of the second PDU includes information for arouting path switch to the second routing path; and transmitting, to thedestination node, the second PDU including the header via the secondrouting path related to the second path ID in the second routing ID.

According to an embodiment of the present disclosure, acomputer-readable medium has recorded thereon a program for performingeach step of a method on a computer, the method comprising: receiving aconfiguration for a first routing identity (ID) and a second routing ID,wherein the first routing ID is related to a first routing path towardsa destination node, and the second routing ID is related to a secondrouting path towards the destination node; transmitting, to thedestination node, a first protocol data unit (PDU) via the first routingpath related to the first path ID in the first routing ID; and based onthat a condition to switch a routing path is satisfied: constructing asecond PDU so that a header of the second PDU includes information for arouting path switch to the second routing path; and transmitting, to thedestination node, the second PDU including the header via the secondrouting path related to the second path ID in the second routing ID.

The present disclosure can have various advantageous effects.

For example, end-to-end packet delay in TAB networks can be reduced.According to the present disclosure, dynamic conditional re-routing canbe achieved in IAB networks.

For example, when some problems occur at a primary routing path towardsa destination node of a packet, the TAB node can use a secondary routingpath towards the same destination node of the packet.

For example, the IAB node can autonomously switch routing path from theprimary routing path to the secondary routing path based on one or moreconfigured conditions for detection of problems at the primary routingpath.

For example, the IAB node may evaluate a condition to switch a routingpath for a specific ingress BH RLC channel for which the condition isconfigured, so that the TAB node can preferentially handle packets withhigh priority.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

FIG. 5 shows an example of IAB topology to which technical features ofthe present disclosure can be applied.

FIG. 6 shows a parent and child node relationship for IAB node to whichtechnical features of the present disclosure can be applied.

FIG. 7 shows an example of a protocol stack for F1-U protocol betweenIAB-DU and IAB donor-CU to which technical features of the presentdisclosure can be applied.

FIG. 8 shows an example of a protocol stack for F1-C protocol betweenIAB-DU and IAB donor-CU to which technical features of the presentdisclosure can be applied.

FIG. 9 shows an example of a protocol stack for TAB-MTs RRC and NASconnections.

FIG. 10 shows an example of routing and BH RLC channel selection on BAPsublayer to which technical features of the present disclosure can beapplied.

FIG. 11 shows an example of a functional view of BAP sublayer to whichtechnical features of the present disclosure can be applied.

FIGS. 12A and 12B show an example of backhaul link problem to whichtechnical features of the present disclosure can be applied.

FIG. 13 shows an example of a routing path switching according to anembodiment of the present disclosure. Steps illustrated in FIG. 13 maybe performed by a wireless device and/or an IAB node.

FIG. 14 shows an example of a structure of BAP PDU including a secondarypath routing indicator according to an embodiment of the presentdisclosure.

FIG. 15 shows an example of a structure of BAP PDU including a secondaryrouting ID according to an embodiment of the present disclosure.

FIG. 16 shows an example of a signal flow for a conditional routing pathswitching according to an embodiment of the present disclosure.

FIG. 17 shows an example of a signal flow for a routing path switchingbased on a congestion control according to an embodiment of the presentdisclosure.

FIG. 18 shows an example of a signal flow for a routing path switchingbased on a BH problem indication according to an embodiment of thepresent disclosure.

FIG. 19 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

FIG. 20 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

FIG. 21 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

DETAILED DESCRIPTION

The technical features described below may be used by a communicationstandard by the 3rd generation partnership project (3GPP)standardization organization, a communication standard by the instituteof electrical and electronics engineers (IEEE), etc. For example, thecommunication standards by the 3GPP standardization organization includelong-term evolution (LTE) and/or evolution of LTE systems. The evolutionof LTE systems includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G newradio (NR). The communication standard by the IEEE standardizationorganization includes a wireless local area network (WLAN) system suchas IEEE 802.11a/b/g/n/ac/ax. The above system uses various multipleaccess technologies such as orthogonal frequency division multipleaccess (OFDMA) and/or single carrier frequency division multiple access(SC-FDMA) for downlink (DL) and/or uplink (UL). For example, only OFDMAmay be used for DL and only SC-FDMA may be used for UL. Alternatively,OFDMA and SC-FDMA may be used for DL and/or UL.

In the present disclosure, “A or B” may mean “only A”, “only B”, or“both A and B”. In other words, “A or B” in the present disclosure maybe interpreted as “A and/or B”. For example, “A. B or C” in the presentdisclosure may mean “only A”, “only B”, “only C”, or “any combination ofA, B and C”.

In the present disclosure, slash (/) or comma (,) may mean “and/or”. Forexample, “A/B” may mean “A and/or B”. Accordingly. “A/B” may mean “onlyA”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, Bor C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B” or “both A and B”. In addition, the expression “at least one ofA or B” or “at least one of A and/or B” in the present disclosure may beinterpreted as same as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A. B and C” maymean “only A”, “only B”, “only C”, or “any combination of A, B and C”.In addition, “at least one of A, B or C” or “at least one of A, B and/orC” may mean “at least one of A, B and C”.

Also, parentheses used in the present disclosure may mean “for example”.In detail, when it is shown as “control information (PDCCH)”, “PDCCH”may be proposed as an example of “control information”. In other words,“control information” in the present disclosure is not limited to“PDCCH”, and “PDDCH” may be proposed as an example of “controlinformation”. In addition, even when shown as “control information(i.e., PDCCH)”, “PDCCH” may be proposed as an example of “controlinformation”.

Technical features that are separately described in one drawing in thepresent disclosure may be implemented separately or simultaneously.

The terms used throughout the disclosure can be defined as thefollowings:

“Integrated access and backhaul (IAB)” refers to a scheme in which apart of a wireless spectrum is used for backhaul connection of basestations instead of fiber (i.e., wireless backhaul). The IAB node may bea kind of a wireless device.

“IAB node” refers to a RAN node that supports wireless access to userequipments (UE)s and wirelessly backhauls the access traffic. The IABnode and the UE may be a kind of a wireless device.

“Backhaul (BH) radio link control (RLC) channel” refers to an RLCchannel between two nodes, which is used to transport backhaul packets.

“Ingress BH RLC channel” refers to an BH RLC channel on which a packetis received by a node.

“Egress BH RLC channel” refers to an BH RLC channel on which a packet istransmitted by a node.

“Ingress link” refers to a radio link on which a packet is received by anode.

“Egress link” refers to a radio link on which a packet is transmitted bya node.

Throughout the disclosure, the terms ‘radio access network (RAN) node’,‘base station’, ‘eNB’, ‘gNB’ and ‘cell’ may be used interchangeably.Further, a UE may be a kind of a wireless device, and throughout thedisclosure, the terms ‘UE’ and ‘wireless device’ may be usedinterchangeably.

Throughout the disclosure, the terms ‘cell quality’, ‘signal strength’.‘signal quality’. ‘channel state’. ‘channel quality’, ‘channelstate/reference signal received power (RSRP)’ and ‘reference signalreceived quality (RSRQ)’ may be used interchangeably.

The following drawings are created to explain specific embodiments ofthe present disclosure. The names of the specific devices or the namesof the specific signals/messages/fields shown in the drawings areprovided by way of example, and thus the technical features of thepresent disclosure are not limited to the specific names used in thefollowing drawings.

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

The 5G usage scenarios shown in FIG. 1 are only exemplary, and thetechnical features of the present disclosure can be applied to other 5Gusage scenarios which are not shown in FIG. 1 .

Referring to FIG. 1 , the three main requirements areas of 5G include(1) enhanced mobile broadband (eMBB) domain. (2) massive machine typecommunication (mMTC) area, and (3) ultra-reliable and low latencycommunications (URLLC) area. Some use cases may require multiple areasfor optimization and, other use cases may only focus on only one keyperformance indicator (KPI). 5G is to support these various use cases ina flexible and reliable way.

eMBB focuses on across-the-board enhancements to the data rate, latency,user density, capacity and coverage of mobile broadband access. The eMBBaims ˜10 Gbps of throughput. eMBB far surpasses basic mobile Internetaccess and covers rich interactive work and media and entertainmentapplications in cloud and/or augmented reality. Data is one of the keydrivers of 5G and may not be able to see dedicated voice services forthe first time in the 5G era. In 5G, the voice is expected to beprocessed as an application simply using the data connection provided bythe communication system. The main reason for the increased volume oftraffic is an increase in the size of the content and an increase in thenumber of applications requiring high data rates. Streaming services(audio and video), interactive video and mobile Internet connectivitywill become more common as more devices connect to the Internet. Many ofthese applications require always-on connectivity to push real-timeinformation and notifications to the user. Cloud storage andapplications are growing rapidly in mobile communication platforms,which can be applied to both work and entertainment. Cloud storage is aspecial use case that drives growth of uplink data rate. 5G is also usedfor remote tasks on the cloud and requires much lower end-to-end delayto maintain a good user experience when the tactile interface is used.In entertainment, for example, cloud games and video streaming areanother key factor that increases the demand for mobile broadbandcapabilities. Entertainment is essential in smartphones and tabletsanywhere, including high mobility environments such as trains, cars andairplanes. Another use case is augmented reality and informationretrieval for entertainment. Here, augmented reality requires very lowlatency and instantaneous data amount.

mMTC is designed to enable communication between devices that arelow-cost, massive in number and battery-driven, intended to supportapplications such as smart metering, logistics, and field and bodysensors. mMTC aims ˜10 years on battery and/or ˜1 million devices/km2.mMTC allows seamless integration of embedded sensors in all areas and isone of the most widely used 5G applications. Potentially by 2020,internet-of-things (IoT) devices are expected to reach 20.4 billion.Industrial IoT is one of the areas where 5G plays a key role in enablingsmart cities, asset tracking, smart utilities, agriculture and securityinfrastructures.

URLLC will make it possible for devices and machines to communicate withultra-reliability, very low latency and high availability, making itideal for vehicular communication, industrial control, factoryautomation, remote surgery, smart grids and public safety applications.URLLC aims ˜1 ms of latency. URLLC includes new services that willchange the industry through links with ultra-reliability/low latency,such as remote control of key infrastructure and self-driving vehicles.The level of reliability and latency is essential for smart gridcontrol, industrial automation, robotics, drones control andcoordination.

Next, a plurality of use cases included in the triangle of FIG. 1 willbe described in more detail.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as a means of delivering streams rated from hundreds of megabitsper second to gigabits per second. This high speed can be required todeliver TVs with resolutions of 4K or more (6K, 8K and above) as well asvirtual reality (VR) and augmented reality (AR). VR and AR applicationsinclude mostly immersive sporting events. Certain applications mayrequire special network settings. For example, in the case of a VR game,a game company may need to integrate a core server with an edge networkserver of a network operator to minimize delay.

Automotive is expected to become an important new driver for 5G, withmany use cases for mobile communications to vehicles. For example,entertainment for passengers demands high capacity and high mobilebroadband at the same time. This is because future users will continueto expect high-quality connections regardless of their location andspeed. Another use case in the automotive sector is an augmented realitydashboard. The driver can identify an object in the dark on top of whatis being viewed through the front window through the augmented realitydashboard. The augmented reality dashboard displays information thatwill inform the driver about the object's distance and movement. In thefuture, the wireless module enables communication between vehicles,information exchange between the vehicle and the supportinginfrastructure, and information exchange between the vehicle and otherconnected devices (e.g. devices accompanied by a pedestrian). The safetysystem allows the driver to guide the alternative course of action sothat he can drive more safely, thereby reducing the risk of accidents.The next step will be a remotely controlled vehicle or self-drivingvehicle. This requires a very reliable and very fast communicationbetween different self-driving vehicles and between vehicles andinfrastructure. In the future, a self-driving vehicle will perform alldriving activities, and the driver will focus only on traffic that thevehicle itself cannot identify. The technical requirements ofself-driving vehicles require ultra-low latency and high-speedreliability to increase traffic safety to a level not achievable byhumans.

Smart cities and smart homes, which are referred to as smart societies,will be embedded in high density wireless sensor networks. Thedistributed network of intelligent sensors will identify conditions forcost and energy-efficient maintenance of a city or house. A similarsetting can be performed for each home. Temperature sensors, windows andheating controllers, burglar alarms and appliances are all wirelesslyconnected. Many of these sensors typically require low data rate, lowpower and low cost. However, for example, real-time high-definition (HD)video may be required for certain types of devices for monitoring.

The consumption and distribution of energy, including heat or gas, ishighly dispersed, requiring automated control of distributed sensornetworks. The smart grid interconnects these sensors using digitalinformation and communication technologies to collect and act oninformation. This information can include supplier and consumerbehavior, allowing the smart grid to improve the distribution of fuel,such as electricity, in terms of efficiency, reliability, economy,production sustainability, and automated methods. The smart grid can beviewed as another sensor network with low latency.

The health sector has many applications that can benefit from mobilecommunications. Communication systems can support telemedicine toprovide clinical care in remote locations. This can help to reducebarriers to distance and improve access to health services that are notcontinuously available in distant rural areas. It is also used to savelives in critical care and emergency situations. Mobile communicationbased wireless sensor networks can provide remote monitoring and sensorsfor parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantin industrial applications. Wiring costs are high for installation andmaintenance. Thus, the possibility of replacing a cable with a wirelesslink that can be reconfigured is an attractive opportunity in manyindustries. However, achieving this requires that wireless connectionsoperate with similar delay, reliability, and capacity as cables and thattheir management is simplified. Low latency and very low errorprobabilities are new requirements that need to be connected to 5G.

Logistics and freight tracking are important use cases of mobilecommunications that enable tracking of inventory and packages anywhereusing location based information systems. Use cases of logistics andfreight tracking typically require low data rates, but require a largerange and reliable location information.

NR supports multiple numerology (or, subcarrier spacing (SCS)) tosupport various 5G services. For example, when the SCS is 15 kHz, widearea in traditional cellular bands may be supported. When the SCS is 30kHz/60 kHz, dense-urban, lower latency and wider carrier bandwidth maybe supported. When the SCS is 60 kHz or higher, a bandwidth greater than24.25 GHz may be supported to overcome phase noise.

The NR frequency band may be defined as two types of frequency range,i.e., FR1 and FR2. The numerical value of the frequency range may bechanged. For example, the frequency ranges of the two types (FR1 andFR2) may be as shown in Table 1 below. For ease of explanation, in thefrequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”,FR2 may mean “above 6 GHz range,” and may be referred to as millimeterwave (mmW).

TABLE 1 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NRsystem may be changed. For example, FR1 may include a frequency band of410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may includea frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. Forexample, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) ormore included in FR1 may include an unlicensed band. Unlicensed bandsmay be used for a variety of purposes, for example for communication forvehicles (e.g., autonomous driving).

TABLE 2 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied. Referringto FIG. 2 , the wireless communication system may include a first device210 and a second device 220.

The first device 210 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, an unmanned aerial vehicle(UAV), an artificial intelligence (AI) module, a robot, an AR device, aVR device, a mixed reality (MR) device, a hologram device, a publicsafety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

The second device 220 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, a UAV, an AI module, arobot, an AR device, a VR device, an MR device, a hologram device, apublic safety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

For example, the UE may include a mobile phone, a smart phone, a laptopcomputer, a digital broadcasting terminal, a personal digital assistant(PDA), a portable multimedia player (PMP), a navigation device, a slatepersonal computer (PC), a tablet PC, an ultrabook, a wearable device(e.g. a smartwatch, a smart glass, a head mounted display (HMD)). Forexample, the HMD may be a display device worn on the head. For example,the HMD may be used to implement AR, VR and/or MR.

For example, the drone may be a flying object that is flying by a radiocontrol signal without a person boarding it. For example, the VR devicemay include a device that implements an object or background in thevirtual world. For example, the AR device may include a device thatimplements connection of an object and/or a background of a virtualworld to an object and/or a background of the real world. For example,the MR device may include a device that implements fusion of an objectand/or a background of a virtual world to an object and/or a backgroundof the real world. For example, the hologram device may include a devicethat implements a 360-degree stereoscopic image by recording and playingstereoscopic information by utilizing a phenomenon of interference oflight generated by the two laser lights meeting with each other, calledholography. For example, the public safety device may include a videorelay device or a video device that can be worn by the user's body. Forexample, the MTC device and the IoT device may be a device that do notrequire direct human intervention or manipulation. For example, the MTCdevice and the IoT device may include a smart meter, a vending machine,a thermometer, a smart bulb, a door lock and/or various sensors. Forexample, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, handling, or preventing a disease.For example, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, or correcting an injury or disorder.For example, the medical device may be a device used for the purpose ofinspecting, replacing or modifying a structure or function. For example,the medical device may be a device used for the purpose of controllingpregnancy. For example, the medical device may include a treatmentdevice, a surgical device, an (in vitro) diagnostic device, a hearingaid and/or a procedural device, etc. For example, a security device maybe a device installed to prevent the risk that may occur and to maintainsafety. For example, the security device may include a camera, aclosed-circuit TV (CCTV), a recorder, or a black box. For example, thefin-tech device may be a device capable of providing financial servicessuch as mobile payment. For example, the fin-tech device may include apayment device or a point of sales (POS). For example, theclimate/environmental device may include a device for monitoring orpredicting the climate/environment.

The first device 210 may include at least one or more processors, suchas a processor 211, at least one memory, such as a memory 212, and atleast one transceiver, such as a transceiver 213. The processor 211 mayperform the functions, procedures, and/or methods of the first devicedescribed throughout the disclosure. The processor 211 may perform oneor more protocols. For example, the processor 211 may perform one ormore layers of the air interface protocol. The memory 212 is connectedto the processor 211 and may store various types of information and/orinstructions. The transceiver 213 is connected to the processor 211 andmay be controlled by the processor 211 to transmit and receive wirelesssignals.

The second device 220 may include at least one or more processors, suchas a processor 221, at least one memory, such as a memory 222, and atleast one transceiver, such as a transceiver 223. The processor 221 mayperform the functions, procedures, and/or methods of the second device220 described throughout the disclosure. The processor 221 may performone or more protocols. For example, the processor 221 may perform one ormore layers of the air interface protocol. The memory 222 is connectedto the processor 221 and may store various types of information and/orinstructions. The transceiver 223 is connected to the processor 221 andmay be controlled by the processor 221 to transmit and receive wirelesssignals.

The memory 212, 222 may be connected internally or externally to theprocessor 211, 212, or may be connected to other processors via avariety of technologies such as wired or wireless connections.

The first device 210 and/or the second device 220 may have more than oneantenna. For example, antenna 214 and/or antenna 224 may be configuredto transmit and receive wireless signals.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

Specifically, FIG. 3 shows a system architecture based on anevolved-UMTS terrestrial radio access network (E-UTRAN). Theaforementioned LTE is a part of an evolved-UTMS (e-UMTS) using theE-UTRAN.

Referring to FIG. 3 , the wireless communication system includes one ormore user equipment (UE) 310, an E-UTRAN and an evolved packet core(EPC). The UE 310 refers to a communication equipment carried by a user.The UE 310 may be fixed or mobile. The UE 310 may be referred to asanother terminology, such as a mobile station (MS), a user terminal(UT), a subscriber station (SS), a wireless device, etc.

The E-UTRAN consists of one or more evolved NodeB (eNB) 320. The eNB 320provides the E-UTRA user plane and control plane protocol terminationstowards the UE 10. The eNB 320 is generally a fixed station thatcommunicates with the UE 310. The eNB 320 hosts the functions, such asinter-cell radio resource management (RRM), radio bearer (RB) control,connection mobility control, radio admission control, measurementconfiguration/provision, dynamic resource allocation (scheduler), etc.The eNB 320 may be referred to as another terminology, such as a basestation (BS), a base transceiver system (BTS), an access point (AP),etc.

A downlink (DL) denotes communication from the eNB 320 to the UE 310. Anuplink (UL) denotes communication from the UE 310 to the eNB 320. Asidelink (SL) denotes communication between the UEs 310. In the DL, atransmitter may be a part of the eNB 320, and a receiver may be a partof the UE 310. In the UL, the transmitter may be a part of the UE 310,and the receiver may be a part of the eNB 320. In the SL, thetransmitter and receiver may be a part of the UE 310.

The EPC includes a mobility management entity (MME), a serving gateway(S-GW) and a packet data network (PDN) gateway (P-GW). The MME hosts thefunctions, such as non-access stratum (NAS) security, idle statemobility handling, evolved packet system (EPS) bearer control, etc. TheS-GW hosts the functions, such as mobility anchoring, etc. The S-GW is agateway having an E-UTRAN as an endpoint. For convenience, MME/S-GW 330will be referred to herein simply as a “gateway,” but it is understoodthat this entity includes both the MME and S-GW. The P-GW hosts thefunctions, such as UE Internet protocol (IP) address allocation, packetfiltering, etc. The P-GW is a gateway having a PDN as an endpoint. TheP-GW is connected to an external network.

The UE 310 is connected to the eNB 320 by means of the Uu interface. TheUEs 310 are interconnected with each other by means of the PC5interface. The eNBs 320 are interconnected with each other by means ofthe X2 interface. The eNBs 320 are also connected by means of the S1interface to the EPC, more specifically to the MME by means of theS1-MME interface and to the S-GW by means of the S1-U interface. The S1interface supports a many-to-many relation between MMEs/S-GWs and eNBs.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

Specifically, FIG. 4 shows a system architecture based on a 5G NR. Theentity used in the 5G NR (hereinafter, simply referred to as “NR”) mayabsorb some or all of the functions of the entities introduced in FIG. 3(e.g. eNB, MME, S-GW). The entity used in the NR may be identified bythe name “NG” for distinction from the LTE/LTE-A.

Referring to FIG. 4 , the wireless communication system includes one ormore UE 410, a next-generation RAN (NG-RAN) and a 5th generation corenetwork (5GC). The NG-RAN consists of at least one NG-RAN node. TheNG-RAN node is an entity corresponding to the eNB 320 shown in FIG. 3 .The NG-RAN node consists of at least one gNB 421 and/or at least oneng-eNB 422. The gNB 421 provides NR user plane and control planeprotocol terminations towards the UE 410. The ng-eNB 422 provides E-UTRAuser plane and control plane protocol terminations towards the UE 410.

The 5GC includes an access and mobility management function (AMF), auser plane function (UPF) and a session management function (SMF). TheAMF hosts the functions, such as NAS security, idle state mobilityhandling, etc. The AMF is an entity including the functions of theconventional MME. The UPF hosts the functions, such as mobilityanchoring, protocol data unit (PDU) handling. The UPF an entityincluding the functions of the conventional S-GW. The SMF hosts thefunctions, such as UE IP address allocation, PDU session control.

The gNBs 421 and ng-eNBs 422 are interconnected with each other by meansof the Xn interface. The gNBs 421 and ng-eNBs 422 are also connected bymeans of the NG interfaces to the 5GC, more specifically to the AMF bymeans of the NG-C interface and to the UPF by means of the NG-Uinterface.

The gNBs 421 may include a gNB-CU (hereinafter, gNB-CU may be simplyreferred to as CU) and at least one gNB-DU (hereinafter, gNB-DU may besimply referred to as DU).

The gNB-CU is a logical node hosting RRC, SDAP and PDCP protocols of thegNB or an RRC and PDCP protocols of the en-gNB. The gNB-CU controls theoperation of the at least one gNB-DU.

The gNB-DU is a logical node hosting RLC. MAC, and physical layers ofthe gNB or the en-gNB. The operation of the gNB-DU is partly controlledby the gNB-CU. One gNB-DU supports one or multiple cells. One cell issupported by only one gNB-DU.

The gNB-CU and gNB-DU are connected via an F1 interface. The gNB-CUterminates the F1 interface connected to the gNB-DU. The gNB-DUterminates the F1 interface connected to the gNB-CU. One gNB-DU isconnected to only one gNB-CU. However, the gNB-DU may be connected tomultiple gNB-CUs by appropriate implementation. The F1 interface is alogical interface. For NG-RAN, the NG and Xn-C interfaces for a gNBconsisting of a gNB-CU and gNB-DUs, terminate in the gNB-CU. ForE-UTRAN-NR dual connectivity (EN-DC), the S1-U and X2-C interfaces for agNB consisting of a gNB-CU and gNB-DUs, terminate in the gNB-CU. ThegNB-CU and connected gNB-DUs are only visible to other gNBs and the 5GCas a gNB.

Functions of the F1 interface includes F1 control (F1-C) functions asfollows.

(1) F1 Interface Management Function

The error indication function is used by the gNB-DU or gNB-CU toindicate to the gNB-CU or gNB-DU that an error has occurred.

The reset function is used to initialize the peer entity after nodesetup and after a failure event occurred. This procedure can be used byboth the gNB-DU and the gNB-CU.

The F1 setup function allows to exchange application level data neededfor the gNB-DU and gNB-CU to interoperate correctly on the F1 interface.The F1 setup is initiated by the gNB-DU.

The gNB-CU configuration update and gNB-DU configuration updatefunctions allow to update application level configuration data neededbetween gNB-CU and gNB-DU to interoperate correctly over the F1interface, and may activate or deactivate cells.

(2) System Information Management Function

Scheduling of system broadcast information is carried out in the gNB-DU.The gNB-DU is responsible for transmitting the system informationaccording to the scheduling parameters available.

The gNB-DU is responsible for the encoding of NR master informationblock (MIB). In case broadcast of system information block type-1 (SIB1)and other SI messages is needed, the gNB-DU is responsible for theencoding of SIB1 and the gNB-CU is responsible for the encoding of otherSI messages.

(3) F1 UE Context Management Function

The F1 UE context management function supports the establishment andmodification of the necessary overall UE context.

The establishment of the F1 UE context is initiated by the gNB-CU andaccepted or rejected by the gNB-DU based on admission control criteria(e.g., resource not available).

The modification of the F1 UE context can be initiated by either gNB-CUor gNB-DU. The receiving node can accept or reject the modification. TheF1 UE context management function also supports the release of thecontext previously established in the gNB-DU. The release of the contextis triggered by the gNB-CU either directly or following a requestreceived from the gNB-DU. The gNB-CU request the gNB-DU to release theUE Context when the UE enters RRC_IDLE or RRC_INACTIVE.

This function can be also used to manage DRBs and SRBs, i.e.,establishing, modifying and releasing DRB and SRB resources. Theestablishment and modification of DRB resources are triggered by thegNB-CU and accepted/rejected by the gNB-DU based on resource reservationinformation and QoS information to be provided to the gNB-DU.

The mapping between QoS flows and radio bearers is performed by gNB-CUand the granularity of bearer related management over F1 is radio bearerlevel. To support packet duplication for intra-gNB-DU carrieraggregation (CA), one data radio bearer should be configured with twoGPRS tunneling protocol (GTP)-U tunnels between gNB-CU and a gNB-DU.

With this function, gNB-CU requests the gNB-DU to setup or change of thespecial cell (SpCell) for the UE, and the gNB-DU either accepts orrejects the request with appropriate cause value.

With this function, the gNB-CU requests the setup of the secondarycell(s) (SCell(s)) at the gNB-DU side, and the gNB-DU accepts all, someor none of the SCell(s) and replies to the gNB-CU. The gNB-CU requeststhe removal of the SCell(s) for the UE.

(4) RRC Message Transfer Function

This function allows to transfer RRC messages between gNB-CU and gNB-DU.RRC messages are transferred over F1-C. The gNB-CU is responsible forthe encoding of the dedicated RRC message with assistance informationprovided by gNB-DU.

A gNB-CU may be functionally split into a gNB-CU-control plane(gNB-CU-CP) and at least one gNB-CU-user plane (gNB-CU-UP). A gNB-CU-CPmay be simply referred to as CU-CP and a gNB-CU-UP may be simplyreferred to as CU-UP. The gNB-CU-CP and the gNB-CU-UP may be included ingNB-CU.

The gNB-CU-CP may be a logical node hosting an RRC and a control planepart of a PDCP protocol of the gNB-CU for a gNB. As illustrated, thegNB-CU-CP is connected to the gNB-DU through F1-C interface. ThegNB-CU-CP terminates an E1 interface connected with the gNB-CU-UP andthe F1-C interface connected with the gNB-DU.

The gNB-CU-UP may be a logical node hosting a user plane part of thePDCP protocol of the gNB-CU for a gNB, and the user plane part of thePDCP protocol and a SDAP protocol of the gNB-CU for a gNB. Asillustrated, the gNB-CU-UP is connected to the gNB-DU through F1-Uinterface, and is connected to the gNB-CU-CP through the E1 interface.The gNB-CU-UP terminates the E1 interface connected with the gNB-Cu-CPand the F1-U interface connected with the gNB-DU.

In CU CP-UP split structure, the following properties may hold:

(1) A gNB-DU may be connected to a gNB-CU-CP.

(2) A gNB-CU-UP may be connected to a gNB-CU-CP.

(3) A gNB-DU can be connected to multiple gNB-CU-UPs under the controlof the same gNB-CU-CP (i.e., the gNB-CU-CP to which the gNB-DU isconnected and the multiple gNB-CU-UPs are connected).

(4) A gNB-CU-UP can be connected to multiple DUs under the control ofthe same gNB-CU-CP (i.e., the gNB-CU-CP to which the gNB-CU-UP isconnected and the multiple DUs are connected).

FIG. 5 shows an example of IAB topology to which technical features ofthe present disclosure can be applied.

Referring to FIG. 5 , the IAB topology may comprise an IAB donor 501 andmultiple IAB nodes 511, 513, 515, 521 and 523. “IAB donor node (or,simply IAB donor)” refers to a RAN node which provides UE's interface tocore network (CN) and wireless backhauling functionalities to IAB nodes.The IAB donor 501 may be treated as a signal logical node that maycomprise a set of functions such as DU, CU-CP, CU-UP and potentiallyother functions. In a deployment, the IAB donor can be split accordingto these functions, which can all be either collocated ornon-collocated. Also, some of the functions presently associated withthe IAB donor may eventually be moved outside of the IAB donor in caseit becomes evident that the functions do not perform IAB-specific tasks.

The IAB donor 501 may be connected to the JAB node 511, 513 and 515 viawireless backhaul link (hereinafter, the terms “wireless backhaul link”and “wireless backhaul channel” can be used interchangeably), and maycommunicate with the IAB node 511, 513 and/or 515 via the wirelessbackhaul link. For example, DUs of the IAB donor 501 may be used tocommunicate with the TAB nodes 511, 513 and/or 515 via wireless backhaullink. Each of the IAB node 511 and 515 may communicate with a UE servedby itself via wireless access link (hereinafter, the term “wirelessaccess link and wireless access channel can be used interchangeably).Further, the IAB donor 501 may be a parent node for the IAB node 511,513 and 515, and the IAB node 511, 513 and 515 may be a child node forthe IAB donor 501. The definition of the parent node and the child nodewill be described later.

The TAB node 513 may be connected to JAB node 521 and 523 via wirelessbackhaul link, and may communicate with the IAB node 521 and/or 523 viawireless backhaul link. The IAB node 521 may communicate with a UEserved by itself via wireless access link. Further, the JAB node 513 maybe a parent node for the JAB node 521 and 523, and the JAB node 521 and523 may be a child node for the TAB node 513.

The JAB nodes 511, 513 and 515 may directly communicate with IAB donor501 via wireless backhaul link. Therefore, the distance between the IABdonor 501 and each of the TAB nodes 511, 513 and 515 may be expressed as1-hop distance. The IAB donor 501 may be 1-hop parent node for the JABnodes 511, 513 and 515, and the JAB nodes 511, 513 and 515 may be 1-hopchild node for the IAB donor 501.

The IAB nodes 521 and 523 may communicate with the IAB donor 501 via afirst wireless backhaul link and a second wireless backhaul link. Thefirst wireless backhaul link may be a wireless backhaul link between i)the JAB node 513 ii) the JAB nodes 521 and/or 523. The second wirelessbackhaul link may be a wireless backhaul link between the JAB node 513and the IAB donor 501. Therefore, the distance between the IAB donor 501and each of the JAB nodes 521 and 523 may be expressed as 2-hopdistance. The IAB donor 501 may be 2-hop parent node for the IAB nodes521 and 523, and the JAB nodes 521 and 523 may be 2-hop child node forthe IAB donor 501. In a similar way. N-hop distance may be definedbetween arbitrary JAB nodes (including or not including IAB donor), andthus, N-hop parent node and N-hop child node may also be defined.

FIG. 6 shows a parent and child node relationship for TAB node to whichtechnical features of the present disclosure can be applied.

Referring to FIG. 6 , an IAB node 611 may be connected to parent nodes601 and 603 via wireless backhaul links, and may be connected to childnodes 621, 623 and 625 via wireless backhaul links. Throughout thedisclosure, “parent IAB node (or, simply parent node)” for an TAB nodemay be defined as a next hop neighbor node with respect to an IAB-mobiletermination (IAB-MT, or simply MT) of the JAB node. That is, theneighbor node on the IAB-MTs interface may be referred to as a parentnode. The parent node can be IAB node or IAB donor-DU. Further, “childJAB node (or, simply child node)” for an IAB node may be defined as anext hop neighbor node with respect to an IAB-DU (or, simply DU) of theJAB node. That is, the neighbor node on the IAB-DU's interface may bereferred to as a child node.

IAB-MT may refer to an JAB node function that terminates the Uuinterface to the parent node. IAB-DU may refer to a gNB-DU functionalitysupported by the JAB node to terminate the access interface to UEs andnext-hop IAB nodes, and/or to terminate the F1 protocol to the gNB-CUfunctionality on the IAB donor.

The direction toward the child node may be referred to as downstreamwhile the direction toward the parent node may be referred to asupstream. Further, a backhaul link between an IAB node and a parent nodefor the IAB node may be referred to as upward backhaul link for the TABnode. A backhaul link between an IAB node and a child node for the IABnode may be referred to as downward backhaul link for the JAB node. Abackhaul link for an JAB node may comprise at least one of an upwardbackhaul link for the TAB node, or a downward backhaul link for the JABnode.

The IAB-node may have redundant routes to the JAB-donor CU.

For IAB-nodes operating in SA-mode, NR dual connectivity (DC) may beused to enable route redundancy m the backhaul (BH) by allowing theIAB-MT to have concurrent BH RLC links with two parent nodes. The parentnodes have to be connected to the same IAB-donor CU-CP, which controlsthe establishment and release of redundant routes via these two parentnodes. The parent nodes together with the IAB-donor CU may obtain theroles of the IAB-MTs master node and secondary node. The NR DC framework(e.g. MCG/SCG-related procedures) may be used to configure the dualradio links with the parent nodes.

FIG. 7 shows an example of a protocol stack for F1-U protocol betweenIAB-DU and IAB donor-CU to which technical features of the presentdisclosure can be applied. FIG. 8 shows an example of a protocol stackfor F1-C protocol between IAB-DU and IAB donor-CU to which technicalfeatures of the present disclosure can be applied. In FIGS. 7-8 , it isexemplary assumed that F1-U and F1-C are carried over 2 backhaul hops.

Referring to FIGS. 7 to 8 , on the wireless backhaul, the IP layer maybe carried over a backhaul adaptation protocol (BAP) sublayer, whichenables routing over multiple hops. The IP laver may be also used forsome non-F1 traffic, such as signalling traffic for the establishmentand management of SCTP associations and the F1-supporting securitylayer.

On each backhaul link, the BAP PDUs may be carried by backhaul (BH)radio link control (RLC) channels. Multiple BH RLC channels can beconfigured on each BH link to allow traffic prioritization and QoSenforcement. The BH-RLC-channel mapping for BAP PDUs may be performed bythe BAP entity on each IAB-node and the IAB-donor.

FIG. 9 shows an example of a protocol stack for IAB-MTs RRC and NASconnections.

Referring to FIG. 9 , protocol stacks for SRB and/or DRB are shown. TheIAB-MT may establish SRBs carrying RRC and NAS and potentially DRBs(e.g. carrying OAM traffic) with the IAB-donor. These SRBs and DRBs maybe transported between the IAB-MT of an JAB node and a parent node forthe IAB node over Uu access channel(s).

In FIGS. 7 to 9 , each of the IAB donor, IAB node 1 and JAB node 2 maycomprise a physical (PHY) layer, a media access control (MAC) layer, aradio link control (RLC) layer, a packet data convergence protocol(PDCP) layer, a radio resource control (RRC) layer and/or a non-accessstratum (NAS) layer.

The PHY layer may belong to layer 1 (L1). The PHY layer offersinformation transfer services to MAC sublayer and higher layers. The PHYlayer offers to the MAC sublayer transport channels. Data between theMAC sublayer and the PHY layer is transferred via the transportchannels. Between different PHY layers, i.e., between a PHY layer of atransmission side and a PHY layer of a reception side, data istransferred via the physical channels.

The MAC sublayer may belong to layer 2 (L2). The main services andfunctions of the MAC sublayer include mapping between logical channelsand transport channels, multiplexing/de-multiplexing of MAC service dataunits (SDUs) belonging to one or different logical channels into/fromtransport blocks (TB) delivered to/from the physical layer on transportchannels, scheduling information reporting, error correction throughhybrid automatic repeat request (HARQ), priority handling between UEs bymeans of dynamic scheduling, priority handling between logical channelsof one UE by means of logical channel prioritization (LCP), etc. The MACsublayer offers to the radio link control (RLC) sublayer logicalchannels.

The RLC sublayer belong to L2. The RLC sublayer supports threetransmission modes, i.e. transparent mode (TM), unacknowledged mode(UM), and acknowledged mode (AM), in order to guarantee various qualityof services (QoS) required by radio bearers. The main services andfunctions of the RLC sublayer depend on the transmission mode. Forexample, the RLC sublayer provides transfer of upper layer PDUs for allthree modes, but provides error correction through ARQ for AM only. InLTE/LTE-A, the RLC sublayer provides concatenation, segmentation andreassembly of RLC SDUs (only for UM and AM data transfer) andre-segmentation of RLC data PDUs (only for AM data transfer). In NR, theRLC sublayer provides segmentation (only for AM and UM) andre-segmentation (only for AM) of RLC SDUs and reassembly of SDU (onlyfor AM and UM). That is, the NR does not support concatenation of RLCSDUs. The RLC sublayer offers to the packet data convergence protocol(PDCP) sublayer RLC channels.

The PDCP sublayer belong to L2. The main services and functions of thePDCP sublayer for the user plane include header compression anddecompression, transfer of user data, duplicate detection, PDCP PDUrouting, retransmission of PDCP SDUs, ciphering and deciphering, etc.The main services and functions of the PDCP sublayer for the controlplane include ciphering and integrity protection, transfer of controlplane data, etc.

A radio resource control (RRC) layer belongs to L3. The RRC layer isonly defined in the control plane. The RRC layer controls radioresources between the UE and the network. To this end, the RRC layerexchanges RRC messages between the UE and the BS. The main services andfunctions of the RRC layer include broadcast of system informationrelated to AS and NAS, paging, establishment, maintenance and release ofan RRC connection between the UE and the network, security functionsincluding key management, establishment, configuration, maintenance andrelease of radio bearers, mobility functions, QoS management functions,UE measurement reporting and control of the reporting, NAS messagetransfer to/from NAS from/to UE.

In other words, the RRC layer controls logical channels, transportchannels, and physical channels in relation to the configuration,reconfiguration, and release of radio bearers. A radio bearer refers toa logical path provided by L1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAPsublayer) for data transmission between a UE and a network. Setting theradio bearer means defining the characteristics of the radio protocollayer and the channel for providing a specific service, and setting eachspecific parameter and operation method. Radio bearer may be dividedinto signaling RB (SRB) and data RB (DRB). The SRB is used as a path fortransmitting RRC messages in the control plane, and the DRB is used as apath for transmitting user data in the user plane.

An RRC state indicates whether an RRC layer of the UE is logicallyconnected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRCconnection is established between the RRC layer of the UE and the RRClayer of the E-UTRAN, the UE is in the RRC connected state(RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE).In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced.RRC_INACTIVE may be used for various purposes. For example, the massivemachine type communications (MMTC) UEs can be efficiently managed inRRC_INACTIVE. When a specific condition is satisfied, transition is madefrom one of the above three states to the other.

A predetermined operation may be performed according to the RRC state.In RRC_IDLE, public land mobile network (PLMN) selection, broadcast ofsystem information (SI), cell re-selection mobility, core network (CN)paging and discontinuous reception (DRX) configured by NAS may beperformed. The UE shall have been allocated an identifier (ID) whichuniquely identifies the UE in a tracking area. No RRC context stored inthe BS.

In RRC_CONNECTED, the UE has an RRC connection with the network (i.e.E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is alsoestablished for UE. The UE AS context is stored in the network and theUE. The RAN knows the cell which the UE belongs to. The network cantransmit and/or receive data to/from UE. Network controlled mobilityincluding measurement is also performed.

Most of operations performed in RRC_IDLE may be performed inRRC_NACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging isperformed in RRC_INACTIVE. In other words, in RRC_IDLE, paging formobile terminated (MT) data is initiated by core network and paging areais managed by core network. In RRC_INACTIVE, paging is initiated byNG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN.Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRXfor RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, inRRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established forUE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knowsthe RNA which the UE belongs to.

NAS layer is located at the top of the RRC layer. The NAS controlprotocol performs the functions, such as authentication, mobilitymanagement, security control.

Further, each of the IAB donor, IAB node 1 and IAB node 2 may comprise aBAP layer/sublayer. The main service and functions of the BAP sublayermay include:

-   -   Transfer of data;    -   Routing of packets to next hop;    -   Determination of BAP destination and path for packets from upper        layers;    -   Determination of egress RLC channels for packets routed to next        hop;    -   Differentiating traffic to be delivered to upper layers from        traffic to be delivered to egress link;    -   Flow control feedback signalling; and/or    -   BH RLF notification.

The IAB-DU's IP traffic may be routed over the wireless backhaul via theBAP sublayer. In downstream direction, IP packets may be encapsulated bythe BAP sublayer at the IAB-donor, and de-encapsulated at thedestination IAB-node. In upstream direction, the upper layer traffic maybe encapsulated at the IAB-node, and de-encapsulated at the IAB-donor.

On the BAP sublayer, packets may be routed based on the BAP routing ID,which is carried in the BAP header. The BAP header may be added to thepacket when the packet arrives from upper layers, and the packet may bestripped off when the packet has reached a destination node of thepacket. The selection of the packet's BAP routing ID may be configuredby the TAB-donor. The BAP routing ID may comprise/consists of BAPaddress and BAP path ID. The BAP address may indicate the destinationnode of the packet on the BAP sublayer, and the BAP path ID may indicatethe routing path the packet should follow to the destination. For thepurpose of routing, each IAB-node may be further configured with adesignated BAP address.

On each hop of the packet's path, the IAB-node may inspect the packet'sBAP address in the routing header to determine if the packet has reachedits destination, i.e., matches the IAB-node's BAP address. In case thepacket has not reached the destination, the IAB-node may determine thenext hop backhaul link, referred to as egress link, based on the BAProuting ID carried in the packet header and a routing configuration theIAB-node received from the IAB-donor.

The TAB-node may also select the BH RLC channel on the designated egresslink. For packets arriving from upper layers, the selection of the BHRLC channel may be configured by the CU, and it is based on upper layertraffic specifiers. Since each BH RLC channel is configured with a QoScode point or priority level, RLC-channel selection may facilitatetraffic-specific prioritization and QoS enforcement on the BH. For F1-Utraffic, it may be possible to map each GTP-U tunnel to a dedicated BHRLC channel or to aggregate multiple GTP-U tunnels into one common BHRLC channel.

When packets are routed from one BH link to another, the BH RLC channelon the egress BH link may be determined based on the mappingconfiguration between ingress BH RLC channels and egress BH RLC channelsprovided by the IAB-donor.

In upstream direction, the IAB-donor CU may configure the IAB-node withmappings between upstream F1- and non-F1-traffic originated at theIAB-node, and the appropriate BAP routing ID and Backhaul RLC channel. Aspecific mapping may be configured:

-   -   for each F1-U GTP-U tunnel;    -   for non-UE associated F1AP messages;    -   for UE-associated F1AP messages of each UE; and/or    -   for non-F1 traffic.

Multiple mappings can contain the same Backhaul RLC channel and/or BAProuting ID.

These configurations may be received via F1AP. During IAB-nodeintegration, before F1AP is established, a default BH RLC channel and adefault BAP routing ID may be configured via RRC, which are used for allupper layer traffic.

In downstream direction, traffic mapping may occur internal to theIAB-donor.

FIG. 10 shows an example of routing and BH RLC channel selection on BAPsublayer to which technical features of the present disclosure can beapplied.

Routing on BAP sublayer may use the BAP routing ID, which is configuredby the IAB-donor. For the routing ID, the flow control information maybe provided in the flow control feedback. The BAP routing ID maycomprise/consist of BAP address and BAP path ID. A length of the routingID may be 20 bits, in which leftmost 10 bits may indicate BAP addressand rightmost 10 bits may indicate BAP path ID. The BAP address may beused for the following purposes:

-   -   1. Determination if a packet has reached the destination node,        i.e. IAB-node or IAB-donor DU, on BAP sublayer. This may be the        case if the BAP address in the packet's BAP header matches the        BAP address configured via RRC on the IAB-node, or via F1AP on        the IAB-donor DU.    -   2. Determination of the next-hop node for packets that have not        reached their destination. This may apply to packets arriving        from a prior hop on BAP sub-layer or that have been received        from IP layer.

For packets arriving from a prior hop, the determination of the next-hopnode may be based on a routing configuration provided by the IAB-donorCU via F1AP signalling. The routing configuration may contain themapping between the BAP routing ID carried in the packet's BAP headerand the next-hop node's BAP address, as specified in table 3:

TABLE 3 BAP routing ID Next-hop BAP address Derived from BAP packet'sBAP header To be used to forward packet

The IAB-node may resolve the next-hop BAP address to a physical backhaullink. For this purpose, LAB-donor CU may provide IAB-node with itschild-node's BAP address in a UE-associated F1AP message and itsparent-node's BAP address in RRC signalling. The IAB-node can receivemultiple routing configurations with the same destination BAP addressbut different BAP path IDs. These routing configurations may resolve tothe same or different egress BH links. In case the BH link has RLF, theIAB-node may select another BH link based on routing entries with thesame destination BAP address, i.e., by disregarding the BAP path ID. Inthis manner, a packet can be delivered via an alternative path in casethe indicated path is not available.

When routing a packet from an ingress to an egress BH link, the IAB-nodemay derive the egress RLC-channel on the egress BH link through an F1AP-configured mapping from the RLC channel used on the ingress BH link.The RLC channel IDs used for ingress and egress BH RLC channels may begenerated by the IAB-donor CU. Since the RLC channel ID only haslink-local scope, the mapping configurations may also include the BAPaddresses of prior and next hop, as specified in table 4:

TABLE 4 Next-hop BAP Prior-hop BAP Ingress RLC Egress RLC addressaddress channel ID channel ID Derived from Derived from Derived from Tobe used on routing packet's packet's egress link to configurationingress link ingress link forward packet

The IAB-node may resolve the BH RLC channel IDs from logical channel IDsbased on the configuration by the IAB-donor. For RLC channels indownstream direction, the RLC channel ID may be included in the F1APconfiguration of the RLC channel. For RLC channels in upstreamdirection, the RLC channel ID may be included in the RRC configurationof the corresponding logical channel. FIG. 11 shows an example of afunctional view of BAP sublayer to which technical features of thepresent disclosure can be applied.

On the IAB-node, the BAP sublayer may contain one BAP entity at the MTfunction and a separate BAP entity at the DU function. On the IAB-donorDU, the BAP sublayer may contain only one BAP entity. Each BAP entitymay have a transmitting part and a receiving part. The transmit part ofthe BAP entity may have a corresponding receiving part of a BAP entityat the IAB node or IAB donor DU across the backhaul link.

The receiving part on the BAP entity may deliver BAP PDUs to thecollocated transmitting part on the BAP entity. Alternatively, thereceiving part may deliver BAP SDUs to the collocated transmitting part.When passing BAP SDUs, the receiving part may remove the BAP header andthe transmitting part may add the BAP header with the same BAP routingID as carried on the BAP PDU header prior to removal. Passing BAP SDUsin this manner may be therefore functionally equivalent to passing BAPPDUs, in implementation.

The transmitting part of the BAP entity on the IAB-MT can receive BAPSDUs from upper layers and BAP Data Units from the receiving part of theBAP entity on the IAB-DU of the same IAB-node, and construct BAP DataPDUs as needed. The transmitting part of the BAP entity on the IAB-DUcan receive BAP Data Units from the receiving part of the BAP entity onthe IAB-MT of the same IAB node and construct BAP Data PDUs as needed.The transmitting part of the BAP entity on the IAB-donor DU can receiveBAP SDUs from upper layers.

Upon receiving a BAP SDU from upper layers, the transmitting part of theBAP entity shall:

-   -   select a BAP address and a BAP path identity for this BAP SDU;    -   construct a BAP Data PDU by adding a BAP header to the BAP SDU,        where the DESTINATION field is set to the selected BAP address        and the PATH field is set to the selected BAP path identity.

When the BAP entity has a BAP Data PDU to transmit, the transmittingpart of the BAP entity shall:

-   -   perform routing to determine the egress link;    -   determine the egress BH RLC channel;    -   submit this BAP Data PDU to the selected egress BH RLC channel        of the selected egress link.

Data buffering on the transmitting part of the BAP entity. e.g., untilRLC-AM entity has received an acknowledgement, may be performed. In caseof BH RLF, the transmitting part of BAP entity may reroute the BAP DataPDUs, which has not been acknowledged by lower layer before the backhaulRLF, to an alternative path.

Upon receiving a BAP Data PDU from lower layer (i.e. ingress BH RLCchannel), the receiving part of the BAP entity shall:

-   -   1> if DESTINATION field of this BAP PDU matches the BAP address        of this node:    -   2> remove the BAP header of this BAP PDU and deliver the BAP SDU        to upper layers.    -   1> else:    -   2> deliver the BAP Data Unit to the transmitting part of the        collocated BAP entity.

When a BAP PDU that contains reserved or invalid values or contains aBAP address which is not included in the configured BH routinginformation received, the BAP entity shall discard the received BAP PDU.

In IAB networks, a certain backhaul link may experience transmissionproblem due to e.g., degradation of backhaul link quality or improperload balancing across the IAB nodes. Degradation of backhaul linkquality may happen frequently if the backhaul link experienced non-lineof sight channel between two neighbour nodes due to blockages or if thebeam-alignment between two neighbour nodes are not properly managed.Improper load balancing may occur due to unexpected surge of trafficarrival in a specific node or unexpected degradation of backhaul linkquality.

A local backhaul link problem can quickly propagate over the neighbournodes due to the nature of the multi-hop transmissions unless propercontrol to tackle such backhaul link problem is introduced. To ensureQoS over multi-hop wireless transmission in IAB networks, it isimportant to exploit path diversity, if available, such that packets ona path with a problem can be dynamically re-routed to another path, whenneeded.

FIGS. 12A and 12B show an example of backhaul link problem to whichtechnical features of the present disclosure can be applied.

Referring to FIG. 12A, a backhaul link problem may occur at a backhaullink BH_yw between IAB node “y” and IAB node “w”. Therefore, upstreamtransmission from TAB node “w” towards IAB donor node via the BH_yw maynot be possible. Referring to FIG. 12B, a backhaul link problem mayoccur at a backhaul link BH_xy between IAB node “x” and IAB node “y”.Therefore, downstream transmission from IAB donor node towards JAB node“w” via the BH_xy may not be possible. However, there is another pathtowards IAB node “w”, by using a backhaul link BH_xz between IAB node“x” and IAB node “z”, and a backhaul link BH_zw between JAB node “z” andJAB node “w”. By using a path including the BH_xz and the BH_zw,downstream transmission from IAB donor node towards JAB node “w” may bepossible.

In an TAB network topology, there may be one or more paths from a sourceIAB node to a destination IAB node. From a single JAB node perspective,the TAB node may have one or multiple next hops for the same destinationnode. For example, the TAB node may have a primary routing path and asecondary routing path for the same destination node. The IAB node maytransmit packets via the primary routing path towards a destinationnode. In some cases, there may be a need for the IAB node to perform arouting path switching from the primary routing path to the secondaryrouting path, and transmit packets via the secondary routing pathtowards the destination node.

FIG. 13 shows an example of a routing path switching according to anembodiment of the present disclosure. Steps illustrated in FIG. 13 maybe performed by a wireless device and/or an IAB node.

Referring to FIG. 13 , in step S1301, the wireless device may receive aconfiguration for a first routing ID and a second routing ID. The firstrouting ID may be related to a first routing path towards a destinationnode. The second routing ID may be related to a second routing pathtowards the destination node.

In step S1303, the wireless device may transmit, to the destinationnode, a first PDU via the first routing path related to the firstrouting ID.

In step S1305, the wireless device may determine whether a condition toswitch a routing path is satisfied. That is, the wireless device mayevaluate the condition to determine whether the condition is satisfiedor not.

If the condition to switch a routing path is satisfied, in step S1307,the wireless device may construct a second PDU so that a header of thesecond PDU includes information for a routing path switch to the secondrouting path.

In step S1309, the wireless device may transmit, to the destinationnode, the second PDU including the header via the second routing pathrelated to the second routing ID.

If the condition to switch a routing path is not satisfied, in stepS1309, the wireless device may transmit, to the destination node, thesecond PDU via the first routing path related to the first routing ID.

According to various embodiments, the first routing ID may comprise adestination ID (e.g., BAP address) for the destination node and a firstpath ID related to the first routing path. The second routing ID maycomprise the destination ID for the destination node and a second pathID related to the second routing path. The first routing ID may be aprimary routing ID, and the second routing ID may be a secondary routingID. The primary routing ID may be a default routing ID, and thesecondary routing ID may be a substitute routing ID for the defaultrouting ID.

According to various embodiments, the information for the routing pathswitch to the second routing path may comprise at least one of: adestination ID for the destination node; an instruction to perform arouting via a substitute routing path towards the destination nodeinformed by the destination ID; or a path ID. The path ID may be theprimary path ID and/or the first path ID. For the introduction, anexplicit inclusion of the instruction in the information for the routingpath switch may be used. Alternatively, the path ID of the informationfor the routing path switch may be set to a particular path ID that ispre-configured to implicitly indicate the instruction. The substituterouting path may be related to a substitute path ID towards thedestination node informed by the destination ID. The substitute routingpath may be related to a substitute routing ID for a default routing ID.The default routing ID may be configured to IAB nodes on a next hop ofthe wireless device. The substitute path ID for the destination ID maybe configured to JAB nodes on a next hop of the wireless device. Thesubstitute path ID for the default path ID towards the destination maybe configured to TAB nodes on a next hop of the wireless device. If anTAB node on the next hop of the wireless device receives a PDU for adestination node and determines that the PDU needs to be routed on asubstitute routing path for the destination based on the presence of theinstruction, the IAB node may determine a substitute routing path forthe received PDU based on the configured substitute path information(i.e., substitute path ID) and transmit the PDU to an IAB node on thenext hop of the determined substitute routing path.

According to various embodiments, the substitute routing ID may be thesecond routing ID, and the substitute routing path may be the secondrouting path.

According to various embodiments, the information for the routing pathswitch to the second routing path may comprise: the destination ID forthe destination node; and a second routing ID. The information for therouting path switch to the second routing path including the secondrouting ID may be used by the IAB nodes on the next hop of the wirelessdevice to perform a routing via the second routing path towards thedestination node, where the second routing path is related to the secondpath ID of the second routing ID, and the destination node is informedby the destination ID in the second routing ID. If an IAB node on thenext hop of the wireless device receives a PDU for a destination nodeand determines that the PDU needs to be routed on a substitute routingpath for the destination by identifying the second routing ID in theheader of the received PDU, the IAB node may transmit the PDU to an IABnode on the next hop of the second routing path.

According to various embodiments, the first routing path and the secondrouting path may be related to different egress backhaul (BH) radio linkcontrol (RLC) channels for a same ingress BH RLC channel.

According to various embodiments, a mapping between each of the firstrouting path and the second routing path and each of the differentegress BH RLC channels may be configured to the wireless device.

According to various embodiments, the condition may be evaluated basedon that packets are received on an ingress backhaul (BH) radio linkcontrol (RLC) channel for which the condition is configured. Evaluationof the condition may comprise determining whether the condition issatisfied or not.

According to various embodiments, an egress backhaul (BH) radio linkcontrol (RLC) channel of the second routing path may be mapped to aningress BH RLC channel for which the condition is configured.

According to various embodiments, the condition may comprise a conditionthat a load balancing is required for a next hop of the wireless deviceon the first routing path.

According to various embodiments, the condition may comprise a conditionthat information informing a backhaul link failure is received from anext hop of the wireless device on the first routing path.

According to various embodiments, the wireless device may be anintegrated access and backhaul (JAB) node.

According to various embodiments, the wireless device may configure aprimary routing ID and a secondary routing ID. The primary routing IDand the secondary routing ID may have a common destination ID butdifferent path ID. The wireless device may configure an egress BH RLCchannel applicable for re-routing and an egress BH RLC channel for anormal routing for each ingress BH RLC channel. The egress BH RLCchannel for re-routing may be associated with the secondary routing ID.The wireless device may receive, on the ingress BH RLC channel, a packetto transmit/forward. The wireless device may construct a packet carryinga payload of the received packet. An indication related to the secondaryrouting ID may be included in a header of the packet based on detectinga backhaul link problem on a primary routing path associated with theprimary routing ID. The wireless device may transmit (or, route) theconstructed packet over a secondary routing path associated with thesecondary routing ID on the egress BH RLC channel for the re-routing.

Hereinafter, details of the routing path switching are described.

The routing path switching may be performed from a primary routing pathto a secondary routing path (However, the routing path switching mayalso be performed reversely). The primary routing path may be related toa primary routing ID, and the secondary routing path may be related to asecondary routing ID.

The secondary routing ID may comprise/consist of BAP address (e.g.,destination ID) for the destination node and a BAP path ID for thesecondary routing path towards the destination node. The secondaryrouting ID may be related to the secondary routing path. The secondaryrouting path may be used as re-routing path towards the destinationnode.

The secondary routing ID may be associated to a primary routing ID. Aconventional routing ID in the BAP may be considered as the primaryrouting ID. That is, the primary routing ID may be a default routing ID,and the secondary routing ID may be a substitute routing ID for thedefault routing ID. The primary routing ID may comprise/consist of BAPaddress (e.g., destination ID) for the destination node and BAP path IDfor a primary routing path towards the destination node. The primaryrouting ID may be related to the primary routing path. The primaryrouting path may be used as a current transmission path towards thedestination node.

An IAB node may be configured with the primary routing ID as well asoptionally the secondary routing ID for the common/same destination ID.

All the IAB nodes on the secondary routing path for the same destinationnode may be configured with the same secondary routing ID (i.e.,secondary routing ID which comprise the same destination ID and/or thesame path ID).

The primary routing path may correspond to a first egress BH RLC channeland the secondary routing path may correspond to a second egress BH RLCchannel.

Furthermore, JAB node may be configured with one or more conditions forconditional re-routing over the secondary routing path. Morespecifically, for each ingress BH RLC channel, the IAB node may beconfigured with whether conditional re-routing is allowed or not for thepackets received on the ingress BH RLC channel. An egress BH RLC channelof the secondary routing path may be configured for each ingress BH RLCchannel for which conditional re-routing is configured/enabled. Theexistence of multiple egress BH RLC channels for the same ingress BH RLCchannel may be interpreted by the IAB node that conditional re-routingis allowed for the packets received on the ingress BH RLC channel. Insuch a case, whether the egress BH RLC channel is associated with theprimary routing path/ID or whether the egress BH RLC channel isassociated with the secondary routing path/ID may be configured.

A list of one or more conditions for conditional re-rerouting may bedefined to detect backhaul link problem and/or to trigger conditionalre-routing to the secondary routing path. Network (or IAB donor node ortopology coordinating node) may configure the one or more conditions forthe IAB node to apply. For each of the one or more conditions forconditional re-routing, entry condition and leaving condition may bedefined. The one or more conditions may comprise at least one of thefollowing conditions 1 to 8:

-   -   1) Condition 1        -   Entry condition: PHY problem is detected (e.g., T310 is            running and/or N310 consecutive “out-of-sync” indications            are received, e.g., over K duration)        -   Leaving condition: PHY problem is resolved (e.g., T310 is            stopped and/or N311 consecutive “in-sync” indications are            received, e.g., over K duration)    -   2) Condition 2        -   Entry condition: early random access (RA) problem is            detected (e.g., the number of RA retransmissions exceeds            threshold)        -   Leaving condition: early RA problem is resolved (e.g., RA is            successful)    -   3) Condition 3        -   Entry condition: early RLC transmission (TX) problem is            detected (the number of RLC retransmissions exceeds            threshold)        -   Leaving condition: early RLC TX problem is resolved (RLC            transmission is successful)    -   4) Condition 4:        -   Entry condition: radio measurement quality of the primary            routing path is worse than radio measurement quality of the            secondary routing path        -   Leaving condition: radio measurement quality of the primary            routing path is better than radio measurement quality of the            secondary routing path (hysteresis can be applied)    -   5) Condition 5        -   Entry condition: reception of flow control information from            the next hop node on the primary routing path, where the            flow control information indicates that the next hop node            experiences congestion.        -   Leaving condition: reception of flow control information            from the next hop node on the primary routing path, where            the flow control information indicates that the next hop no            longer experiences congestion.    -   6) Condition 6        -   Entry condition: detection of buffer load exceeding a            certain level for transmission on the primary routing path.        -   Leaving condition: detection of buffer load going below a            certain level for transmission on the primary routing path.    -   7) Condition 7        -   Entry condition: reception of BH link problem occurrence            indication from the next hop node on the primary routing            path.        -   Leaving condition: reception of BH link recovery indication            from the next hop node on the primary routing path.    -   8) Condition 8        -   Entry condition: detection of BH link problem occurrence on            the primary routing path.        -   Leaving condition: detection of recovery from BH link            problem occurrence on the primary routing path.

Network may indicate to the IAB node which condition among the one ormore conditions presented above should be allowed for an IAB node forthe conditional re-routing.

More than one secondary routing ID can be configured to the IAB node forthe same destination node. In this case, network may configure whichcondition is associated with a specific secondary routing ID.

If the TAB node detects an entry condition for a packet or packet flowfor which secondary routing ID is configured, the TAB node may transmitthe packet over the secondary routing path related to the secondaryrouting ID. Depending on how to set/construct the header of the packetto send over the secondary routing path, one of the following options asillustrated in FIGS. 14-15 may be considered.

FIG. 14 shows an example of a structure of BAP PDU including a secondarypath routing indicator according to an embodiment of the presentdisclosure.

Referring to FIG. 14 , BAP PDU transmitted over a primary routing path(or simply primary path) may comprise a payload and a BAP headerincluding a primary routing ID.

Further. BAP PDU transmitted over a secondary routing path (or, simplysecondary path) may comprise a payload and a BAP header including aprimary routing ID and/or a secondary path routing indicator. For thepacket being re-routed to the secondary routing path, the IAB node mayset a special flag (i.e., secondary path routing indicator) or add thespecial flag to the BAP header of the packet to indicate that the packetis required to be transmitted over the secondary routing path.

In other words, the secondary routing ID may comprise/consist of thesame BAP address (e.g., destination ID) as that in the primary routingID and/or BAP path ID for the secondary routing path. For the packetbeing re-routed, the IAB node may set a special flag or add a specialflag, denoted by “secondary path routing indicator”, to the BAP headerof the packet. The TAB node may select the next hop in accordance withthe secondary routing ID and select the egress BH RLC channel mapped tothe ingress BH RLC channel for conditional re-routing. The special flagin the BAP header may force the subsequent forwarding TAB nodes to applythe secondary routing ID associated with the primary routing ID includedin the BAP header. Subsequent IAB nodes may also use the secondaryrouting ID for transmitting/forwarding/routing the packet. That is, ifan TAB node receives a packet for which the special flag is set/addedand the TAB node is configured with the secondary routing ID applicablefor the packet, the IAB node should forward the packet according to thesecondary routing ID and mapping between the ingress BH RLC channel andegress BH RLC channel configured for conditional re-routing. If TAB nodereceives a packet for which the special flag is set/added but the IABnode is not configured with the secondary routing ID or egress BH RLCchannel mapped to the ingress BH RLC channel applicable for conditionalre-routing of the packet, the TAB node may discard the packet.

FIG. 15 shows an example of a structure of BAP PDU including a secondaryrouting ID according to an embodiment of the present disclosure.

Referring to FIG. 15 , BAP PDU transmitted over a primary routing pathmay comprise a payload and a BAP header including a primary routing ID.The primary routing ID may comprise a destination ID and a primary pathID.

Further. BAP PDU transmitted over a secondary routing path may comprisea payload and a BAP header including a secondary routing ID. Thesecondary routing ID may comprise the destination ID same as thatincluded in the primary routing ID, and a secondary path ID. For thepacket being re-routed to the secondary routing path, the IAB node mayreplace the primary routing ID with the secondary routing ID applicablefor the same destination ID. The secondary routing ID consists of thesame destination ID and the secondary path ID.

In other words, the IAB node may replace the primary routing ID in theBAP header of the packet with the secondary routing ID. The secondaryrouting ID may comprise/consist of the same BAP address (e.g.,destination ID) as that in the primary routing ID and/or BAP path ID forthe secondary routing path. The subsequent forwarding IAB node which hasreceived the BAP header of BAP PDU including the secondary routing IDmay transmit BAP PDU to the destination node informed by the secondaryrouting ID via a secondary routing path informed by the secondaryrouting ID.

If the IAB node does not detect an entry condition for a packet orpacket flow for which secondary routing ID is configured and/or if theIAB node detect a leaving condition for a packet or a packet flow forwhich secondary routing ID is configured after entry condition has beenmet, the IAB node may transmit the packet according to the primaryrouting ID.

FIG. 16 shows an example of a signal flow for a conditional routing pathswitching according to an embodiment of the present disclosure. In FIG.16 , IAB node W may be a destination node. The primary routing path goesthrough IAB node Z. The secondary routing path goes through IAB node Y.The primary routing path is mapped to the primary routing ID. Thesecondary routing path is mapped to the secondary routing ID.

Referring to FIG. 16 , in step S1601, IAB node X may receive aconfiguration of a primary routing ID and a secondary routing ID, sothat the IAB node X is configured with a primary routing path and asecondary routing path towards IAB node W.

In step S1603, IAB node X may be configured with one or more conditionsfor conditional re-routing.

In step S1605, TAB node X may transmit data using the primary routingID. In other words, the data may be transmitted over the primary routingpath towards TAB node W via IAB node Z.

In step S1607, IAB node X may detect a condition for conditionalre-routing over the secondary routing path. That is, the IAB node X maydetect an entry condition for conditional re-routing.

In step S1609, IAB node X may transmit data using the secondary routingID. In other words, the data may be transmitted over the secondaryrouting path towards IAB node W via JAB node Y.

In step S1611. IAB node X may detect a condition for switching back tothe primary routing path. That is, the IAB node X may detect a leavingcondition for switching back to the primary routing path.

In step S1613, IAB node X may transmit data using the primary routingID. In other words, the data may be transmitted over the primary routingpath towards IAB node W via IAB node Z.

FIG. 17 shows an example of a signal flow for a routing path switchingbased on a congestion control according to fan embodiment of the presentdisclosure. In FIG. 17 , IAB node W is a destination node. The primaryrouting path goes through IAB node Z. The secondary routing path goesthrough JAB node Y. The primary routing path is mapped to a primaryrouting ID. The secondary routing path is mapped to a secondary routingID.

Referring to FIG. 17 , in step S1701, IAB node X may receive aconfiguration of a primary routing ID and a secondary routing ID, sothat the IAB node X may be configured with a primary routing path and asecondary routing path towards IAB node W.

In step S1703, TAB node X may be configured with congestion controlfeedback based re-routing.

In step S1705, IAB node X may transmit data using the primary routingID. In other words, the data may be transmitted over the primary routingpath towards JAB node W via JAB node Z.

In step S1707. IAB node X may receive, from IAB node Z over the primaryrouting path, congestion control feedback information indicating thatthe primary routing path experiences congestion.

In step S1709, IAB node X may transmit data using the secondary routingID. In other words, the data may be transmitted over the secondaryrouting path towards TAB node W via TAB node Y.

In step S1711, IAB node X may receive, from IAB node Z over the primaryrouting path, congestion control feedback information indicating thatthe primary routing path no longer experiences congestion.

In step S1713, IAB node X transmits data using the primary routing ID.In other words, the data is transmitted over the primary routing pathtowards IAB node W via IAB node Z.

FIG. 18 shows an example of a signal flow for a routing path switchingbased on a BH problem indication according to an embodiment of thepresent disclosure. In FIG. 18 , IAB node W is a destination node. Theprimary routing path goes through IAB node Z. The secondary routing pathgoes through TAB node Y. The primary routing path is mapped to a primaryrouting ID. The secondary routing path is mapped to a secondary routingID.

Referring to FIG. 18 , in step S1801, IAB node X may receive aconfiguration of a primary routing ID and a secondary routing ID, sothat the IAB node X may be configured with a primary routing path and asecondary routing path towards IAB node W.

In step S1803, IAB node X may be configured with BH problem indicationbased re-routing.

In step S1805, IAB node X may transmit data using the primary routingID. In other words, the data may be transmitted over the primary routingpath towards IAB node W via IAB node Z

In step S1807, IAB node X may receive, from IAB node Z over the primaryrouting path, BH problem indication indicating that the BH problemoccurs at the primary routing path.

In step S1809, IAB node X may transmit data using the secondary routingID. In other words, the data may be transmitted over the secondaryrouting path towards IAB node W via IAB node Y.

In step S1811, IAB node X may receive, from IAB node Z over the primaryrouting path, BH recovery indication indicating that the BH problem atthe primary routing path has recovered.

In step S1813, IAB node X may transmit data using the primary routingID. In other words, the data may be transmitted over the primary routingpath towards IAB node W via IAB node Z.

Hereinafter, an apparatus for a wireless device and/or an IAB node(e.g., first device 210 in FIG. 2 ) in a wireless communication system,according to various embodiments of the present disclosure, will bedescribed.

For example, the wireless device and/or the IAB node may include atleast one processor (e.g., processor 211 in FIG. 2 ), a transceiver(e.g., transceiver 213 in FIG. 2 ), and a memory (e.g., memory 212 inFIG. 2 ).

For example, the at least one processor may be configured to be coupledoperably with the memory and the transceiver.

The at least one processor may be configured to control the transceiverto receive a configuration for a first routing ID and a second routingID. The first routing ID may be related to a first routing path towardsa destination node. The second routing ID may be related to a secondrouting path towards the destination node. The at least one processormay be configured to control the transceiver to transmit, to thedestination node, a first PDU via the first routing path related to thefirst path ID in the first routing ID. Based on that a condition toswitch a routing path is satisfied, the at least one processor may beconfigured to: i) construct a second PDU so that a header of the secondPDU includes information for a routing path switch to the second routingpath; and ii) control the transceiver to transmit, to the destinationnode, the second PDU including the header via the second routing pathrelated to the second path ID in the second routing ID.

The first routing ID may comprise a destination ID (e.g., BAP address)for the destination node and a first path ID related to the firstrouting path. The second routing ID may comprise the destination ID forthe destination node and a second path ID related to the second routingpath. The first routing ID may be a primary routing ID, and the secondrouting ID may be a secondary routing ID. The primary routing ID may bea default routing ID, and the secondary routing ID may be a substituterouting ID for the default routing ID.

The information for the routing path switch to the second routing pathmay comprise: a destination ID for the destination node; and aninstruction to perform a routing via a substitute routing path towardsthe destination node informed by the destination ID. The substituterouting path may be related to a substitute routing ID for a defaultrouting ID. The default routing ID and the substitute routing ID may beconfigured to a next hop of the wireless device.

The substitute routing ID may be the second routing ID, and thesubstitute routing path may be the second routing path.

The information for the routing path switch to the second routing pathmay comprise the second routing ID. The information for the routing pathswitch to the second routing path including the second routing ID may beused to perform a routing via the second routing path towards thedestination node, where the second routing path is related to the secondpath ID of the second routing ID, and the destination node is informedby the destination ID in the second routing ID.

The first routing path and the second routing path may be related todifferent egress backhaul (BH) radio link control (RLC) channels for asame ingress BH RLC channel.

A mapping between each of the first routing path and the second routingpath and each of the different egress BH RLC channels may be configuredto the wireless device.

The condition may be evaluated based on that packets are received on aningress backhaul (BH) radio link control (RLC) channel for which thecondition is configured. Evaluation of the condition may comprisedetermining whether the condition is satisfied or not.

An egress backhaul (BH) radio link control (RLC) channel of the secondrouting path may be mapped to an ingress BH RLC channel for which thecondition is configured.

The condition may comprise a condition that a load balancing is requiredfor a next hop of the wireless device on the first routing path.

The condition may comprise a condition that information informing abackhaul link failure is received from a next hop of the wireless deviceon the first routing path.

The wireless device may be an integrated access and backhaul (IAB) node.

The at least one processor may be configured to configure a primaryrouting ID and a secondary routing ID. The primary routing ID and thesecondary routing ID may have a common destination ID but different pathID. The at least one processor may be configured to configure an egressBH RLC channel applicable for re-routing and an egress BH RLC channelfor a normal routing for each ingress BH RLC channel. The egress BH RLCchannel for re-routing may be associated with the secondary routing ID.The at least one processor may be configured to control the transceiverto receive, on the ingress BH RLC channel, a packet to transmit/forward.The at least one processor may be configured to construct a packetcarrying a payload of the received packet. An indication related to thesecondary routing ID may be included in a header of the packet based ondetecting a backhaul link problem on a primary routing path associatedwith the primary routing ID. The at least one processor may beconfigured to control the transceiver to transmit (or, route) theconstructed packet over a secondary routing path associated with thesecondary routing ID on the egress BH RLC channel for the re-routing.

FIG. 19 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

Referring to FIG. 19 , the wireless communication system may include afirst device 1910 (i.e., first device 210) and a second device 1920(i.e., second device 220).

The first device 1910 may include at least one transceiver, such as atransceiver 1911, and at least one processing chip, such as a processingchip 1912. The processing chip 1912 may include at least one processor,such a processor 1913, and at least one memory, such as a memory 1914.The memory may be operably connectable to the processor 1913. The memory1914 may store various types of information and/or instructions. Thememory 1914 may store a software code 1915 which implements instructionsthat, when executed by the processor 1913, perform operations of thefirst device 910 described throughout the disclosure. For example, thesoftware code 1915 may implement instructions that, when executed by theprocessor 1913, perform the functions, procedures, and/or methods of thefirst device 1910 described throughout the disclosure. For example, thesoftware code 1915 may control the processor 1913 to perform one or moreprotocols. For example, the software code 1915 may control the processor1913 to perform one or more layers of the radio interface protocol.

The second device 1920 may include at least one transceiver, such as atransceiver 1921, and at least one processing chip, such as a processingchip 1922. The processing chip 1922 may include at least one processor,such a processor 1923, and at least one memory, such as a memory 1924.The memory may be operably connectable to the processor 1923. The memory1924 may store various types of information and/or instructions. Thememory 1924 may store a software code 1925 which implements instructionsthat, when executed by the processor 1923, perform operations of thesecond device 1920 described throughout the disclosure. For example, thesoftware code 1925 may implement instructions that, when executed by theprocessor 1923, perform the functions, procedures, and/or methods of thesecond device 1920 described throughout the disclosure. For example, thesoftware code 1925 may control the processor 1923 to perform one or moreprotocols. For example, the software code 1925 may control the processor1923 to perform one or more layers of the radio interface protocol.

According to various embodiments, the first device 1910 as illustratedin FIG. 19 may comprise a wireless device. The wireless device maycomprise a transceiver 1911, a processing chip 1912. The processing chip1912 may comprise a processor 1913, and a memory 1914. The memory 1914may be operably connectable to the processor 1913. The memory 1914 maystore various types of information and/or instructions. The memory 1914may store a software code 1915 which implements instructions that, whenexecuted by the processor 1913, perform operations comprising: receivinga configuration for a first routing identity (ID) and a second routingID—the first routing ID is related to a first routing path towards adestination node, and the second routing ID is related to a secondrouting path towards the destination node; transmitting, to thedestination node, a first protocol data unit (PDU) via the first routingpath related to the first path ID in the first routing ID; and based onthat a condition to switch a routing path is satisfied: constructing asecond PDU so that a header of the second PDU includes information for arouting path switch to the second routing path; and transmitting, to thedestination node, the second PDU including the header via the secondrouting path related to the second path ID in the second routing ID.

According to various embodiments, a computer-readable medium havingrecorded thereon a program for performing each step of a method on acomputer is provided. The method comprises: receiving a configurationfor a first routing identity (ID) and a second routing ID—the firstrouting ID is related to a first routing path towards a destinationnode, and the second routing ID is related to a second routing pathtowards the destination node; transmitting, to the destination node, afirst protocol data unit (PDU) via the first routing path related to thefirst path ID in the first routing ID; and based on that a condition toswitch a routing path is satisfied: constructing a second PDU so that aheader of the second PDU includes information for a routing path switchto the second routing path; and transmitting, to the destination node,the second PDU including the header via the second routing path relatedto the second path ID in the second routing ID.

The present disclosure may be applied to various future technologies,such as AI, robots, autonomous-driving/self-driving vehicles, and/orextended reality (XR).

<AI>

AI refers to artificial intelligence and/or the field of studyingmethodology for making it. Machine learning is a field of studyingmethodologies that define and solve various problems dealt with in AI.Machine learning may be defined as an algorithm that enhances theperformance of a task through a steady experience with any task.

An artificial neural network (ANN) is a model used in machine learning.It can mean a whole model of problem-solving ability, consisting ofartificial neurons (nodes) that form a network of synapses. An ANN canbe defined by a connection pattern between neurons in different layers,a learning process for updating model parameters, and/or an activationfunction for generating an output value. An ANN may include an inputlayer, an output layer, and optionally one or more hidden layers. Eachlayer may contain one or more neurons, and an ANN may include a synapsethat links neurons to neurons. In an ANN, each neuron can output asummation of the activation function for input signals, weights, anddeflections input through the synapse. Model parameters are parametersdetermined through learning, including deflection of neurons and/orweights of synaptic connections. The hyper-parameter means a parameterto be set in the machine learning algorithm before learning, andincludes a learning rate, a repetition number, a mini batch size, aninitialization function, etc. The objective of the ANN learning can beseen as determining the model parameters that minimize the lossfunction. The loss function can be used as an index to determine optimalmodel parameters in learning process of ANN.

Machine learning can be divided into supervised learning, unsupervisedlearning, and reinforcement learning, depending on the learning method.Supervised learning is a method of learning ANN with labels given tolearning data. Labels are the answers (or result values) that ANN mustinfer when learning data is input to ANN. Unsupervised learning can meana method of learning ANN without labels given to learning data.Reinforcement learning can mean a learning method in which an agentdefined in an environment learns to select a behavior and/or sequence ofactions that maximizes cumulative compensation in each state.

Machine learning, which is implemented as a deep neural network (DNN)that includes multiple hidden layers among ANN, is also called deeplearning. Deep learning is part of machine learning. In the following,machine learning is used to mean deep learning.

FIG. 20 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

The AI device 2000 may be implemented as a stationary device or a mobiledevice, such as a TV, a projector, a mobile phone, a smartphone, adesktop computer, a notebook, a digital broadcasting terminal, a PDA, aPMP, a navigation device, a tablet PC, a wearable device, a set-top box(STB), a digital multimedia broadcasting (DMB) receiver, a radio, awashing machine, a refrigerator, a digital signage, a robot, a vehicle,etc.

Referring to FIG. 20 , the AI device 200 may include a communicationpart 2010, an input part 1210, a learning processor 2030, a sensing part2040, an output part 2050, a memory 2060, and a processor 2070.

The communication part 2010 can transmit and/or receive data to and/orfrom external devices such as the AI devices and the AI server usingwire and/or wireless communication technology. For example, thecommunication part 2010 can transmit and/or receive sensor information,a user input, a learning model, and a control signal with externaldevices. The communication technology used by the communication part2010 may include a global system for mobile communication (GSM), a codedivision multiple access (CDMA), an LTE/LTE-A, a 5G, a WLAN, a Wi-Fi,Bluetooth™, radio frequency identification (RFID), infrared dataassociation (IrDA), ZigBee, and/or near field communication (NFC).

The input part 1210 can acquire various kinds of data. The input part1210 may include a camera for inputting a video signal, a microphone forreceiving an audio signal, and a user input part for receivinginformation from a user. A camera and/or a microphone may be treated asa sensor, and a signal obtained from a camera and/or a microphone may bereferred to as sensing data and/or sensor information. The input part1210 can acquire input data to be used when acquiring an output usinglearning data and a learning model for model learning. The input part1210 may obtain raw input data, in which case the processor 2070 or thelearning processor 2030 may extract input features by preprocessing theinput data.

The learning processor 2030 may learn a model composed of an ANN usinglearning data. The learned ANN can be referred to as a learning model.The learning model can be used to infer result values for new input datarather than learning data, and the inferred values can be used as abasis for determining which actions to perform. The learning processor2030 may perform AI processing together with the learning processor ofthe AI server. The learning processor 2030 may include a memoryintegrated and/or implemented in the AI device 2000. Alternatively, thelearning processor 2030 may be implemented using the memory 2060, anexternal memory directly coupled to the AI device 2000, and/or a memorymaintained in an external device.

The sensing part 2040 may acquire at least one of internal informationof the AI device 2000, environment information of the AI device 2000,and/or the user information using various sensors. The sensors includedin the sensing part 2040 may include a proximity sensor, an illuminancesensor, an acceleration sensor, a magnetic sensor, a gyro sensor, aninertial sensor, an RGB sensor, an IR sensor, a fingerprint recognitionsensor, an ultrasonic sensor, an optical sensor, a microphone, a lightdetection and ranging (LIDAR), and/or a radar.

The output part 2050 may generate an output related to visual, auditory,tactile, etc. The output part 2050 may include a display unit foroutputting visual information, a speaker for outputting auditoryinformation, and/or a haptic module for outputting tactile information.

The memory 2060 may store data that supports various functions of the AIdevice 2000. For example, the memory 2060 may store input data acquiredby the input part 1210, learning data, a learning model, a learninghistory, etc.

The processor 2070 may determine at least one executable operation ofthe AI device 2000 based on information determined and/or generatedusing a data analysis algorithm and/or a machine learning algorithm. Theprocessor 2070 may then control the components of the AI device 2000 toperform the determined operation. The processor 2070 may request,retrieve, receive, and/or utilize data in the learning processor 2030and/or the memory 2060, and may control the components of the AI device2000 to execute the predicted operation and/or the operation determinedto be desirable among the at least one executable operation. Theprocessor 2070 may generate a control signal for controlling theexternal device, and may transmit the generated control signal to theexternal device, when the external device needs to be linked to performthe determined operation. The processor 2070 may obtain the intentioninformation for the user input and determine the user's requirementsbased on the obtained intention information. The processor 2070 may useat least one of a speech-to-text (STT) engine for converting speechinput into a text string and/or a natural language processing (NLP)engine for acquiring intention information of a natural language, toobtain the intention information corresponding to the user input. Atleast one of the STT engine and/or the NLP engine may be configured asan ANN, at least a part of which is learned according to a machinelearning algorithm. At least one of the ST engine and/or the NLP enginemay be learned by the learning processor 2030 and/or learned by thelearning processor of the AI server, and/or learned by their distributedprocessing. The processor 2070 may collect history information includingthe operation contents of the AI device 2000 and/or the user's feedbackon the operation, etc. The processor 2070 may store the collectedhistory information in the memory 2060 and/or the learning processor2030, and/or transmit to an external device such as the AI server. Thecollected history information can be used to update the learning model.The processor 2070 may control at least some of the components of AIdevice 2000 to drive an application program stored in memory 2060.Furthermore, the processor 2070 may operate two or more of thecomponents included in the AI device 2000 in combination with each otherfor driving the application program.

FIG. 21 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

Referring to FIG. 21 , in the AI system, at least one of an AI server2120, a robot 2200 a, an autonomous vehicle 2200 b, an XR device 2200 c,a smartphone 2200 d and/or a home appliance 2200 e is connected to acloud network 2100. The robot 2200 a, the autonomous vehicle 2200 b, theXR device 2200 c, the smartphone 2200 d, and/or the home appliance 2200e to which the AI technology is applied may be referred to as AI devices2200 a to 2200 e.

The cloud network 2100 may refer to a network that forms part of a cloudcomputing infrastructure and/or resides in a cloud computinginfrastructure. The cloud network 2100 may be configured using a 3Gnetwork, a 4G or LTE network, and/or a 5G network. That is, each of thedevices 2200 a to 2200 e and 2120 consisting the AI system may beconnected to each other through the cloud network 2100. In particular,each of the devices 2200 a to 2200 e and 2120 may communicate with eachother through a base station, but may directly communicate with eachother without using a base station.

The AI server 2120 may include a server for performing AI processing anda server for performing operations on big data. The AI server 2120 isconnected to at least one or more of AI devices constituting the AIsystem, i.e. the robot 2200 a, the autonomous vehicle 2200 b, the XRdevice 2200 c, the smartphone 2200 d and/or the home appliance 2200 ethrough the cloud network 2100, and may assist at least some AIprocessing of the connected AI devices 2200 a to 2200 e. The AI server2120 can learn the ANN according to the machine learning algorithm onbehalf of the AI devices 2200 a to 2200 e, and can directly store thelearning models and/or transmit them to the AI devices 2200 a to 2200 e.The AI server 2120 may receive the input data from the AI devices 2200 ato 2200 e, infer the result value with respect to the received inputdata using the learning model, generate a response and/or a controlcommand based on the inferred result value, and transmit the generateddata to the AI devices 2200 a to 2200 e. Alternatively, the AI devices2200 a to 2200 e may directly infer a result value for the input datausing a learning model, and generate a response and/or a control commandbased on the inferred result value.

Various embodiments of the AI devices 2200 a to 2200 e to which thetechnical features of the present disclosure can be applied will bedescribed. The AI devices 2200 a to 2200 e shown in FIG. 21 can be seenas specific embodiments of the AI device 2000 shown in FIG. 20 .

The present disclosure can have various advantageous effects.

For example, end-to-end packet delay in IAB networks can be reduced.According to the present disclosure, dynamic conditional re-routing canbe achieved in IAB networks.

For example, when some problems occur at a primary routing path towardsa destination node of a packet, the IAB node can use a secondary routingpath towards the same destination node of the packet.

For example, the IAB node can autonomously switch routing path from theprimary routing path to the secondary routing path based on one or moreconfigured conditions for detection of problems at the primary routingpath.

For example, the IAB node may evaluate a condition to switch a routingpath for a specific ingress BH RLC channel for which the condition isconfigured, so that the IAB node can preferentially handle packets withhigh priority.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod. Other implementations are within the scope of the followingclaims.

1. A method performed by a wireless device in a wireless communication system, the method comprising: receiving a configuration for a first routing identity (ID) and a second routing ID, wherein the first routing ID is related to a first routing path towards a destination node, and the second routing ID is related to a second routing path towards the destination node; transmitting, to the destination node, a first protocol data unit (PDU) via the first routing path related to the first routing ID; and based on that a condition to switch a routing path is satisfied: constructing a second PDU so that a header of the second PDU includes information for a routing path switch to the second routing path; and transmitting, to the destination node, the second PDU including the header via the second routing path related to the second routing ID.
 2. The method of claim 1, wherein the first routing ID comprises a destination ID for the destination node and a first path ID related to the first routing path, and wherein the second routing ID comprises the destination ID for the destination node and a second path ID related to the second routing path.
 3. The method of claim 1, wherein the information for the routing path switch to the second routing path comprises: a destination ID for the destination node; and an instruction to perform a routing via a substitute routing path towards the destination node informed by the destination ID, wherein the substitute routing path is related to a substitute routing ID.
 4. The method of claim 3, wherein the substitute routing ID is the second routing ID, and the substitute routing path is the second routing path.
 5. The method of claim 4, wherein the second routing ID is configured to nodes on a next hop of the wireless device for each destination ID or for each routing ID.
 6. The method of claim 2, wherein the information for the routing path switch to the second routing path comprises the second routing ID.
 7. The method of claim 6, wherein the information for the routing path switch to the second routing path including the second routing ID is used to perform a routing via the second routing path towards the destination node, wherein the second routing path is related to the second path ID of the second routing ID, and the destination node is informed by the destination ID in the second routing ID.
 8. The method of claim 1, wherein the first routing path and the second routing path are related to different egress backhaul (BH) radio link control (RLC) channels for a same ingress BH RLC channel.
 9. The method of claim 8, wherein a mapping between each of the first routing path and the second routing path and each of the different egress BH RLC channels is configured to the wireless device.
 10. The method of claim 1, wherein the condition is evaluated based on that packets are received on an ingress backhaul (BH) radio link control (RLC) channel for which the condition is configured.
 11. The method of claim 1, wherein an egress backhaul (BH) radio link control (RLC) channel of the second routing path is mapped to an ingress BH RLC channel for which the condition is configured.
 12. The method of claim 1, wherein the condition comprises a condition that a load balancing is required for a next hop of the wireless device on the first routing path.
 13. The method of claim 1, wherein the condition comprises a condition that information informing a backhaul link failure is received from a next hop of the wireless device on the first routing path.
 14. The method of claim 1, wherein the condition comprises a condition that transmission delay to a next hop of the wireless device on the first routing path is longer than a threshold.
 15. The method of claim 1, wherein the wireless device is in communication with at least one of a user equipment, a network, or autonomous vehicles other than the wireless device.
 16. A wireless device configured to operate in a wireless communication system, the wireless device comprising: a transceiver; at least one processor; and at least one memory operatively coupled to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising: receiving, through the transceiver, a configuration for a first routing identity (ID) and a second routing ID, wherein the first routing ID is related to a first routing path towards a destination node, and the second routing ID is related to a second routing path towards the destination node; transmitting, through the transceiver to the destination node, a first protocol data unit (PDU) via the first routing path related to a first path ID in the first routing ID; and based on that a condition to switch a routing path is satisfied: constructing a second PDU so that a header of the second PDU includes information for a routing path switch to the second routing path; and transmitting, through the transceiver to the destination node, the second PDU including the header via the second routing path related to a second path ID in the second routing ID.
 17. (canceled)
 18. A computer-readable medium having recorded thereon a program that, based on being executed by at least one processor, perform operations that comprise: receiving a configuration for a first routing identity (ID) and a second routing ID, wherein the first routing ID is related to a first routing path towards a destination node, and the second routing ID is related to a second routing path towards the destination node; transmitting, to the destination node, a first protocol data unit (PDU) via the first routing path related to a first path ID in the first routing ID; and based on that a condition to switch a routing path is satisfied: constructing a second PDU so that a header of the second PDU includes information for a routing path switch to the second routing path; and transmitting, to the destination node, the second PDU including the header via the second routing path related to a second path ID in the second routing ID. 